im trying to find a spell that will help to keep spirits from looking through or being able to pass through a mirror. have a friend, no not me, whom keeps seeing something looking at her through her mirror. maybe something like a mirror wash?

Mirrors are said to be a look into the self, and in some cultures, a look into the Otherworld (specifically citing Celtic lore where one uses a black mirror for scrying, among other examples). If you want to, you can cleanse the mirror, though your friend may want to talk to the spirit seen in the mirror before deciding to rid herself of the spirit's presence right off the bat.